Photo: Shu Suehiro, CC BY 3.0 · source
Pruning guide · Bulb or tuber
Tree dahlia: when and how to prune
Dahlia imperialis
Tree dahlia is best pruned in November.
| Pruning months | November |
|---|---|
| Flowering | October–November |
| Good for bees, butterflies and birds | Yes, for bees |
| Native to Belgium | No, planted |
Tree dahlia: when to prune it?
After the first night frost, usually in November, as soon as the stems have turned black.
What else to prune in those months? November
Tree dahlia: how to prune it?
- Cut the stems back to about 15 cm above the tuber.
- Lift the tubers carefully, let them dry for a few days and store them dry and frost-free.
- If you leave the plant in its pot, cut the stems back as well and put the pot away dry and frost-free.
How much to cut, and how often?
- One pruning period a year: November.
What does it mean for wildlife?
- Tree dahlia flowers in October–November, when it attracts bees.
- If pruning falls during flowering, wait until it is over or leave part of the plant to flower, so bees and butterflies still benefit.
Caution: Do not cut before the first frost: the green stems still feed the tubers and flowering is late.
Nearby: related pruning guides
Plant profile: Tree dahlia · Pruning calendar and basic rules
This guide is compiled from the Bladwijzer plant profile and pruning calendar.